Re: [B.A.T.M.A.N.] [PATCH 1/3] batman-adv: fix lockdep splat when doing mcast_free

Sven Eckelmann:

Maybe the relevant parts of the Oops can be added to the commit message:

WARNING: CPU: 0 PID: 238 at net/batman-adv/multicast.c:142 batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]()
[...]
Call Trace:
 [<ffffffff815fc597>] dump_stack+0x4b/0x64
 [<ffffffff810b34dc>] warn_slowpath_common+0xbc/0x120
 [<ffffffffa0024ec5>] ? batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]
 [<ffffffff810b3705>] warn_slowpath_null+0x15/0x20
 [<ffffffffa0024ec5>] batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]
 [<ffffffffa00273fe>] batadv_mcast_free+0x36/0x39 [batman_adv]
 [<ffffffffa0020c77>] batadv_mesh_free+0x7d/0x13f [batman_adv]
 [<ffffffffa0036a6b>] batadv_softif_free+0x15/0x25 [batman_adv]
 [...]

I agree

...

I see it calls batadv_tt_local_remove() but this does not really requires the lock. Maybe you wanted to perform *all* the removes before TT could do a commit ? Or is there any other reason?

Cheers,

mcast.mla_list is protected by tt.commit_lock (see batadv_mcast_mla_tt_add, batadv_mcast_mla_list_free and batadv_mcast_mla_tt_retract).

ok, this makes sense :)

Simon, I'd suggest you follow Sven's suggestion about adding the oops/stacktrace and then you can also append my

Acked-by: Antonio Quartulli antonio@meshcoding.com

note that this patch is a bugfix, hence it should target maint.

Cheers,